Aerosol-Cloud-Precipitation-Climate Interactions: Evidences and Challenges
Atmospheric aerosols scatter and absorb solar radiation and hence affect weather and climate. Certain aerosols act as cloud condensation nuclei (CCN) and ice-nuclei (IN), and contribute to the cloud formation and development and thus affecting the cloud cycling mechanisms. Present knowledge concerning impact of aerosols on clouds, monsoon activity and climate is incomplete and needs to be studied by collecting systematic observational evidence. In addition, the complex role of aerosols in the climate system in influencing the atmospheric radiation budget is not clear. Impact of anthropogenic pollution on natural clouds is not understood. Aerosols affect clouds in two broad ways: (i) Presence of more number of aerosols lead to formation of more smaller droplets, reduce coalescence, resulting in brighter clouds that reflect more solar energy back to space, hence they contribute to cooling of the Earth’s surface, and (ii) Numerous smaller cloud droplets tend to reduce precipitation and change the extent of cloud cover and increases cloud life time and albedo. One of our recent studies on aerosols over the Indo Gangetic Plains (IGP) relative to the pristine oceans to the south of Indian Ocean showed that highly absorbing aerosols could potentially lead to the revival of active condition preceded by long break. The absorption of solar radiation by aerosols such as black carbon and desert dust also produces surface cooling and local stabilization of lower atmosphere. This stability effect is overcome by the enhanced moisture convergence due to the meridional gradient of aerosol-induced heating. In some other studies, we showed association between cloud to sub-cloud ratio, aerosol variability (in terms of aerosol optical depth and aerosol index) and monsoon precipitation and climate over regional scale.
Aerosols Clouds Lidar Solar Radiometry Radiation Satellites
Panuganti C.S. Devara
Indian Institute of Tropical Meteorology,Pune,Maharashtra,411 008,India
国际会议
西安
英文
11-17
2011-08-17（万方平台首次上网日期，不代表论文的发表时间）